A study is conducted to test the association between smoking status (smoker, non-smoker) and incidence of lung disease (yes, no). What is the null hypothesis for the Chi Square Test for Independence?

• A. Non-smokers have a higher incidence of lung disease.
• B. Smoking causes lung disease.
• C. There is an association between smoking status and incidence of lung disease.
• D. There is no association between smoking status and incidence of lung disease.

Answer: (D)